- Yawning is defined as "the involuntary act
of opening the mouth widely, accompanied by deep
inspiration, and frequently stretching of the
arme, shoulders, and chest to assist in the
inspiratory act followed by relaxation of the
muscles invoived, usually performed when sleepy
or bored" [1].
-
- All my life I have been acutely aware of the
yawns of those about me (e.g., audiences
lecture, fraternizers at cocktail parties, my
wife). It is this cognizance that led to my
recognition of yawning as an early sign of a
vasovagal reflex or reaction. Noxious stimuli
(e.g., needle sticks, contrast media, release of
histamine, rectal distension, fear, and other
somatic avants) can cause the vagal brainstem
nuclei to discharge impulses that lead to
acetylcholine-mediated effects on the arterioles
and the sinoartrial node, resulting in
hypotension and bradycardia. The potential
seriousness of these reactions is well
documented in the medical literature,
particularly for patients who have underlying
coronary and cerebral vascular disease
[2].
-
- Many signs and symptoms of vasovagal reflex
and reaction have been reported: apprehension,
restlessness, dizziness, faintness, intestinal
cramping, nausea, salivation, sweating,
palpitation, dyspnea, syncope, and
unconsciousness [3].
-
- I have noticed that in most of the vasovagal
reflexes or reactions encounter, yawning is the
first manifestation.
-
- According to definition, yawning is caused
by sleepiness or boredom, but I do not think
that patients who are undergoing needle sticks,
angiography, or barium enemas are ever bored,
and their premedication probably does not make
them sleepy. Premedication may put them to
sleep, but there is no middle ground. So, if a
patient begins yawning during a barium enema or
a breast localization, place the patient supine,
measure the pulse and blood pressure, elevate
the patient's legs or place the patient in the
Trendelenburg position, open the IV Unes, and
have the atropine ready. If measures to expand
fluid volume are not successful (and beware of
patients who are in heart failure), 0.6-0.8 mg
of IV atropine usually will reverse the reaction
[4].
-
- References
- Blakinstons Gould medical dictionary, 4th
ed. New York: McGraw-Hill, 1979:1491
- Newton TH, Potts DG, eds. Radiology of the
skull and brain, vol. 2, book 1: Angiography.
St. Louis: Mosby, 1974:1034
- Andrews EJ. The vagus reaction as a possible
cause of severe complications of radiologic
procedures. Radiology 1976;121:1-4
- Kadir S. Diagnostic angiography.
Philadelphie: Saunders, 1976:688-689
- Askenasy JJ Is
yawning an arousal defense reflex ?
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